TW202021901A - Method for the recycling or disposal of halocarbons - Google Patents

Abstract

The present invention relates to a method for recycling and/or disposal of halocarbons, particularly fluorinated alkanes, such as trifluoromethane, by reacting said halocarbons with sulfur trioxide, particularly to form halide sulfonic acids and sulfur dioxide。

Description

Method for recovery or disposal of halocarbon compounds

The present invention relates to a method for the recovery and/or disposal of halocarbon compounds (especially fluoroalkanes, such as trifluoromethane). By reacting halocarbon compounds with sulfur trioxide, especially the formation of hydrogen halide, Carbon dioxide and sulfur dioxide. Recycling/disposal in the meaning of the present invention means the conversion of halocarbon compounds into useful substances.

Halocarbon compounds refer to compounds in which at least one hydrogen atom in a hydrocarbon is replaced by halogen. Hydrocarbons can be any type of hydrocarbons, namely alkanes, alkenes, and alkynes, which can be linear, branched, or cyclic, substituted or unsubstituted. Halogenated alkanes are part of halocarbon compounds, also known as halogenalkanes or alkyl halides. Its structure is a type of compound derived by substituting halogen atoms for one or more hydrogen atoms in alkanes. Haloalkanes are widely used as flame retardants, fire extinguishing agents, refrigerants, propellants, solvents and drugs.

Hydrochlorofluoroalkane (hydrochlorofluoroalkane) was banned internationally in the last century (Montreal Protocol, 1987) due to the destruction of the ozone layer, which induced the development of novel halothanes for other applications as refrigerants and gas propellants The alternative option. The unique properties of halothane, such as high stability and inertness, make it an ideal substitute for hydrochlorofluorocarbon. However, subsequent research and development show that halothane is a potential greenhouse gas. For example, the greenhouse effect of a small fluoroform (CF ₃ H) has the same potential as 14,800 CO ₂ molecules.

The internationally succeeded in gradually banning the use of halothane, and compared to the baseline by 2045, it will be reduced by 85% (the Kigali amendment passed in 2016 for the Montreal Protocol). Alternative gases with low global warming potential and harmless to the ozone layer are currently being studied, and many successful products have been used in the market.

However, many large-scale industrial processes produce halothane as a by-product. For example, the synthesis of chlorodifluoromethane (HCF ₂ Cl) as a refrigerant, the blending component for foaming materials, and polytetrafluoroethylene (Teflon), will produce a large amount of CF ₃ H, and In order to comply with current regulations, additional costs for storage or recycling are caused. The storage of halothane is not economically feasible, so recycling becomes the only reasonable option.

Some current methods (A. McCulloch published the title "Incineration of HFC-23 waste streams to reduce emissions from HFCFC-22: Science, Technology, and Economic Review (Incineration of HFC-23 waste streams for abatement of emissions from HFCFC) -22 production: A review of scientific, technical and economic aspects)”, University of Bristol (University of Bristol, 2005) uses H ₂ and CO ₂ to perform thermal catalytic decomposition of halothane at 300 to 900 ^o C. Produce CO and HF. High temperature operation and HF generation are the main limitations of these methods being widely used. For the recovery system of halocarbon compounds (especially halothane) derived from industrial-scale manufacturing, novel methods are needed.

The object of the present invention is therefore to provide a novel method for the recovery or disposal of halocarbon compounds (especially halothanes), and to convert them into substances that are harmless to the ozone layer and do not exhibit equivalent global warming potential. . In particular, the object of the present invention is to provide an effective method for converting halocarbon compounds into useful substances.

Surprisingly, it was found that the halocarbon compound reacts with SO ₃ to form a sulfonic acid with the halogen of the halocarbon compound. In the first embodiment, the object of the present invention is thus achieved by a method for conversion of halocarbon compounds, in which halocarbon compounds react with SO ₃ , preferably halocarbon compounds and oleum In the reaction, oleum is fuming sulfuric acid. It refers to a solution of SO ₃ dissolved in H ₂ SO ₄ . If stored, SO ₃ reacts with H ₂ SO ₄ to form disulfuric acid. If disulfuric acid is used as a component of the reaction, it is usually decomposed into SO ₃ and H ₂ SO ₄ , so SO ₃ is usually the reaction partner participating in the reaction.

In the meaning of the present invention, a halocarbon compound is a compound in which at least one hydrogen atom in a hydrocarbon is replaced by a halogen. Hydrocarbons can be any type of hydrocarbons, namely alkanes, alkenes, and alkynes, which can be linear, branched, or cyclic, substituted or unsubstituted. And within the scope of the present invention, if the hydrocarbon is an aryl compound, such as phenol, naphthol, benzol, etc., substitution in this context is understood as a hydrogen atom or a C or CH group in a halogenated carbon compound Or the CH ₂ group or the CH ₃ group is substituted by a substituent. This substituent can be -COOH, C(O), N, P, S, O, C(O)O, where, if necessary, free valences are saturated with hydrogen.

If the reaction of halocarbon compounds with SO ₃ is mentioned in the following, it should be understood that the reaction is with pure SO ₃ or with fuming sulfuric acid. Preferably, the fuming sulfuric acid is present to allow the halocarbon compound to react with SO ₃ . Within the scope of the present invention, sulfuric acid or water is provided in the first step and then added SO ₃ , so that fuming sulfuric acid is formed in situ in the reaction mixture. Of course, it is also possible to provide SO ₃ first, and then add water or sulfuric acid, which will also form oleum.

SO ₃ can be dissolved in H ₂ SO ₄ in a wide range of concentrations. Therefore, in the meaning of this application, oleum includes 1% to 100% by weight of SO _{3. The} content of SO ₃ in oleum is preferably 10% to 95%, especially 15% to 90%, which is more Preferably it is 20% to 88%, more preferably 25% to 85% or 30% to 80%, particularly 35% to 75% or 40% to 70%. Preferably, the SO ₃ content is 65% by weight or less, especially 60% by weight or less. Under the safe reaction between halocarbon compounds and fuming sulfuric acid, the higher the SO ₃ content, the higher the risk of treating fuming sulfuric acid and controlling the reaction conditions. If the SO ₃ concentration is low, especially below 10%, the reaction time is quite long. Therefore, especially when the concentration of SO ₃ in fuming sulfuric acid is 25% to 70% by weight, preferably 30% to 65% by weight, effective reaction can proceed.

In this application, if not explicitly stated otherwise,% always refers to% by weight.

Specifically, halocarbon compounds react with sulfur trioxide to form corresponding sulfonic acids. The corresponding sulfonic acid in this context refers to a sulfonic acid that includes the same halogen (F, Cl, Br, I, As) as the halocarbon compound used. Where the halocarbon compound includes more than one type of halogen (F, Cl, Br, I, As), multiple types of sulfonic acid are formed.

For example, if HCF ₃ reacts with fuming sulfuric acid, the reaction products are FSO ₃ H, SO ₂ and CO ₂ . SO ₂ has high solubility in fuming sulfuric acid. It can be re-oxidized to SO ₃ and subsequently used in the recovery of another halocarbon compound. FSO ₃ H can be used as an industrial chemical substance, and CO ₂ has a significantly smaller global warming potential value than the halocarbon compounds undergoing conversion.

Or, if H ₂ CF ₂ reacts with fuming sulfuric acid to form FSO ₃ H: CH ₂ F ₂ + 2SO ₃ + H ₂ SO ₄ à CH ₂ (SO ₄ H) ₂ + 3FSO ₃ H; CH ₂ F ₂ and FA The oleum reaction produces fluorosulfonic acid and methylene di(sulfate) (MDS). The difference from a similar reaction using CHF ₃ is that the carbon does not undergo an oxidation reaction. Therefore, neither the formation of CO ₂ nor SO ₂ was observed.

MDS is basically a formaldehyde derivative. When hydrolyzed, formaldehyde and sulfuric acid are released. MDS in its condensed dimer form is suitable as a biocide, a slow-release antifungal agent for artificial panels (antibacterial and anti-corrosion multifunctional non-formaldehyde straw artificial panels), and as an electrolyte in battery applications.

Without being bound by theory, the following reactions usually occur (where X is a halogen): CH ₂ X ₂ + 2SO ₃ + H ₂ SO ₄ à CH ₂ (SO ₃ H) ₂ + 2XSO ₃ H, X=F CH ₂ X ₂ + 2SO ₃ à CH ₂ (SO ₃ X) ₂ , X=Cl, Br, I CH ₂ X ₂ Excessive reaction: CH ₂ (SO ₃ X) ₂ + CH ₂ X ₂ à 2 XCH ₂ (SO ₃ X)

The following hydrolysis reactions will proceed under respective reaction conditions: CH ₂ (SO ₃ X) ₂ + 2H ₂ O à CH ₂ (SO ₄ H) ₂ + 2HX 2HX + SO ₃ à 2XSO ₃ H CH ₂ (SO ₃ X) ₂ + H ₂ O à (XSO ₃ )-CH ₂ -(SO ₄ H) + HX HX + SO ₃ à XSO ₃ H

The hypothetical response is illustrated below:

Not only an alkane containing one carbon atom can be converted into the corresponding sulfonic acid, an alkane with a higher carbon number can also be converted into the corresponding sulfonic acid. The halocarbon compound that can be converted by fuming sulfuric acid requires at least one structural element, which can perform nucleophilic attack, electrophilic attack, or free radical attack. Such as double bond or triple bond or CH, C-Cl, -C-Br, CI, C-COOH, C-SO ₂ H, or C-SO ₃ H, C-NH ₂ , C-OH, C=O , CN group.

Preferably, the halocarbon compound includes two, three, or four carbon atoms, and the reaction mixture includes not only the halocarbon compound and fuming sulfuric acid, but also an oxidant. The oxidant needs to be added in a stoichiometric amount relative to the content of halocarbon compounds present in the reaction mixture. Suitable oxidizing agents such as peroxides, H ₂ O ₂ , K ₂ S ₂ O ₈ and other stable compounds. The oxidizer will be discussed in more detail below.

Halocarbon compounds that can be recovered/disposed according to the method of the present invention are, for example, F ₃ C-CHF=CH ₂ (1234yf), which is a refrigerant used in air conditions (especially air conditions in automobiles and other vehicles). Similarly, the compound, fuming sulfuric acid and oxidant react to produce SO ₂ and FSO ₃ H. In addition, long-chain halocarbon compounds, such as halogens with -COOH or -SO ₃ H end groups, can be converted into XSO ₃ H (X is halogen) and SO ₂ by adding fuming sulfuric acid. Both linear and cyclic halocarbon compounds can be converted using the method of the present invention.

The method of the present invention provides a simple and inexpensive method for the recovery or disposal of halocarbon compounds and the conversion of halocarbon compounds into useful substances, especially halocarbon compounds produced as by-products in industrial processes, such as Teflon (Teflon). The method of the present invention can be directly carried out with small-scale equipment on the original site where halocarbon compounds are produced.

The method for converting halocarbon compounds using sulfur trioxide in the present invention can be carried out without using any metal catalyst. Preferably, the method of the present invention is carried out without a metal catalyst.

The method of the present invention can use peroxides or dilute peroxide salts (such as K ₂ S ₂ O ₈ ) formed in situ as a catalyst or be carried out in a stoichiometric amount. In principle, any peroxide that is stable at room temperature can be used as a catalyst. In particular, peroxyacids containing oxoacids or salts thereof can be used. More specifically, peroxyacids or their salts, which are oxoacids of sulfur, can be used. Alternatively, a mixture of hydrogen peroxide and oxyacid can be used. Specific examples include: H ₂ S ₂ O ₈ , K ₂ S ₂ O ₈ , Na ₂ S ₂ O ₈ , H ₂ SO ₅ , KHSO ₅ , NaHSO ₅ and so on. These catalysts/oxidants can re-oxidize SO ₂ to SO ₃ . Therefore, the amount of SO ₃ can be reduced. This effect is particularly related to the halocarbon compound including only one carbon atom system.

When the number of carbons in the halocarbon compound is> 1, that is, 2, 3, 4, 5, 6, 7, 8, 9, 10 or higher, the stoichiometric addition of the oxidant seems to be necessary. Here, the oxidant activates the halocarbon compound, which tends to degrade. With the aid of an oxidation catalyst/oxidating agent/oxidant, the progress of the reaction can be more reactive. Without being bound by theory, it is assumed that the oxidation catalyst/oxidant, especially the peroxide system, helps to oxidize the alkyl chain to CO ₂ . An oxidation catalyst and an oxidating agent or oxidant are used for the same compound. The catalytic amount of the added catalyst is less than the stoichiometric amount; if peroxide is used as an oxidating agent or oxidant, it is added in a stoichiometric amount. The oxidating agent and oxidant are synonymous in this application.

The halocarbon compound can be pressurized to its vapor pressure, or used in a liquid form if the halocarbon compound is liquid at room temperature.

Preferably, sulfur trioxide is used in excess relative to the amount of halocarbon compound. The molar ratio of halocarbon compound and sulfur trioxide is preferably 1:100 to 1:1, more preferably 1:25 to 1:1, especially 1:5 to 1:3.

In a preferred embodiment, the reaction of the halocarbon compound and sulfur trioxide is carried out at a temperature in the range of 0 °C to 200 °C. Preferably, the temperature is 20 °C to 180 °C, especially 50 °C to 160 °C, preferably 60 °C to 150 °C, more preferably 80 °C to 125 °C, such as 100 °C to 120 °C. The higher the reaction temperature, the faster and more effective the reaction. However, if the temperature is too high, an extremely severe situation will occur. Therefore, it is necessary to use a reactor that is stable under such conditions. The temperature range is between 80 °C and 130 °C, the reaction is effective, and any standard equipped reactor can be used, so it is economical. In addition, at higher temperatures, the solubility of SO ₂ in H ₂ SO ₄ becomes poor. When the reaction is in equilibrium, if the product is removed, the reaction can be improved. Higher concentrations of oleum allow higher SO ₂ tolerance, thus increasing yield. Based on the solvation of SO ₂ in H ₂ SO ₄ , SO ₂ is quasi removed, thereby increasing the effectiveness of the reaction. If SO ₂ and CO _{2 are} formed, their removal can be carried out, for example, using an absorbent including a 20% by weight NaOH solution.

In a preferred embodiment, the reaction of the halocarbon compound and sulfur trioxide is carried out at a pressure of 1 to 200 bar. Preferably, the pressure is in the range of 10 to 100 bar, especially 25 to 40 bar.

The halocarbon compound may include any halogen. Preferably, the halocarbon compound is a fluorinated, chlorinated and/or brominated derivative of alkanes, or alkenes, or alkynes. The halocarbon compound may include one or more halogen atoms. The halogen atoms may all be the same halogen element, that is, all the halogen atoms may be fluorine atoms, chlorine atoms, or bromine atoms. Alternatively, the halocarbon compound may include more than one type of halogen, for example, both fluorine and chlorine, both fluorine and bromine, both chlorine and bromine, or fluorine, chlorine and bromine.

The halocarbon compound includes at least one halogen atom bonded to a carbon atom. The halocarbon compound may include one or more carbon atoms bonded to one or more halogen atoms. Halocarbon compounds are generally represented by C _n H _(2n+2)-m X _m . In a simpler way, it can be expressed as RX _m , where R is alkyl, alkenyl, or aryl, and X is F, Cl, or Br. Preferably, X is F. The number of halogen atoms is limited only to the number of available bonds, that is, if all hydrogen atoms of the compound are substituted, X corresponds to the number of hydrogen atoms in the R group. At least, m=1.

Halocarbon compounds are halogenated derivatives of alkanes, alkenes, or alkynes. The alkane, or alkene, or alkyne is preferably branched or unbranched alkane, or alkene, or alkyne, wherein the carbon number is 1 to 20, especially 1 to 15, preferably 1 to 10, especially It is 1 to 5. It should be understood that all numbers within the above range are also disclosed. For example, if the carbon number is 1 to 20, it means 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19 or 20. The preferred range is similarly deduced.

In a preferred embodiment, the alkane is methane, ethane, propane, butane, isopentane or isobutane.

Preferably, the halocarbon compound is HCF ₃ , F ₃ C-CHF=CH ₂ , Lindane, halogen representative surfactant or halogenated sulfonic acid surfactant, 1,1,1,2-tetrafluoro Ethane (R134), PFOAs (perfluorooctanoic acid), CH ₂ F ₂ , CH ₃ F, CF ₄ , all environmentally hazardous refrigerants including F and/or Cl, and refrigerants including F and/or Cl.

In a preferred embodiment, the reaction mixture may include a co-catalyst MR, where M is a metal, preferably a transition metal having an oxidation state of +1 to +7, especially the first row transition metal, and R is -H,- OH, -CH ₃ , -O-CH ₃ , -F, -Cl, -Br, -C ₂ H ₅ or higher carbon number alkane, -OC ₂ H ₅ or higher carbon number oxane, or suitable inorganic Counter ion. In particular, metal salts such as CuCl, NiSO ₄ , CoCl ₂ , MnCl ₂ or VCl ₂ are preferable.

In a particularly preferred embodiment of the present invention, the halocarbon compound is a fluoroalkane. In this embodiment, the object of the present invention is achieved by decomposing halothane into HSO ₃ F, CO ₂ and SO ₂ in fuming sulfuric acid.

In a preferred embodiment, the halothane includes at least one compound of the following formula (I): RF _x (I), wherein R is a branched or unbranched alkyl group, especially methyl, ethyl, propyl, butyl An alkyl group, an isopropyl group, an isobutyl group, or a higher carbon number alkyl group, wherein any position of the alkyl group on the secondary or tertiary carbon can be optionally halogenated with a fluorine atom. x is the number of fluorine atoms, and the maximum number of fluorine atoms is the number of saturated fluorocarbon molecules needed.

The halothane can be pressurized to its vapor pressure or used in a liquid form if the halothane is liquid at room temperature. The reaction formula of halothane decomposition is as follows: C _x F _y + SO ₃ (oleum) à HSO ₃ F + CO ₂ + SO ₂ (R1) where x and y are the same or different in the range of 1 to 20 Integer.

Fluorosulfuric acid (HSO ₃ F) is considered to be a mixture of sulfuric acid anhydride and hydrogen fluoride, so it is a precursor of HF. The application of HSO ₃ F, among other examples, includes as a catalyst for alkylation, isomerization, cycloaddition, ring-opening polymerization and fluorosulfonation. SO ₂ can be easily formed into SO _{3 and} then recovered, and the global warming potential value represented by the produced CO ₂ is not high compared to halothane (for example, when CO ₂ is 1, CF ₃ H is 14,800).

With the help of HSO ₃ F having a wide liquid range (melting point = -89.0 ^o C, boiling point = 162.7 ^o C) and the relatively low boiling point of SO ₃ (boiling point = 45 ^o C), highly concentrated HSO ₃ F sulfuric acid can be easily obtained Solution, thus achieving the separation of HSO ₃ F. The unused SO ₃ can be recycled for use in the second batch. This strategy provides an easy and safer alternative to the decomposition of halothane into simple molecules. The formation of fluorosulfuric acid (HSO ₃ F) prevents the corrosive and highly toxic HF from being released into the reactor, so the traditional materials used in the reactor (for example, stainless steel) can be used.

In a preferred embodiment, the product mixture of halocarbon compounds (especially halothane) after decomposition can be separated by distilling off SO ₂ (recovered to H ₂ SO ₄ ) and SO ₃ . Optionally, FSO ₃ H can be used because it is in a mixture containing fuming sulfuric acid.

SO ₂ and CO ₂ can be separated by being absorbed by NaOH solution.

Methylene bis(chlorosulfate) ( MBCS , CH ₂ (SO ₃ Cl) ₂ ), chloromethyl chlorosulfate ( CMCS , ClCH ₂ (SO ₃ Cl)) can be obtained from the reaction mixture in CH ₂ Cl ₂ Extracted out. The volatile CH ₂ Cl _{2 was} evaporated to produce pure product.

Methylene bis(halosulfate) (MBXS, CH ₂ (SO ₃ X) ₂ ), halomethyl halosulfate ( XMXS , XCH ₂ (SO ₃ X)), where X=halogen F, Cl, Br, I. It can be extracted from the reaction mixture in a suitable solvent, such as CH ₂ Cl ₂ , CHCl ₃ , hexafluorobenzene, perfluorinated solvent, and partially fluorinated solvent.

The equipment used for the recovery method of halocarbon compounds, especially halothane, may include a stainless steel reactor, wherein halocarbon compounds, especially halothane, can be added in liquid or gaseous state, depending on the specific vapor pressure of each reagent. Since HF is generated in this method and is retained as HSO ₃ F, there is no need to use a specific substance. If halocarbons, especially halothanes, are gases, the reactor will be pressurized to an appropriate pressure, which allows proper solubility in the fuming sulfuric acid.

The equipment used for the decomposition of halocarbon compounds can be installed next to the industrial process for producing halocarbon compounds, especially halothane, to avoid transportation costs. Alternatively, the device can be deployed in the overall equipment for generating SO ₃ and widely used as the current infrastructure.

In an alternative embodiment, the object of the present invention is achieved by a method of decomposing halothane in fuming sulfuric acid. The method includes the following steps: i) Provide smoky sulfuric acid with a concentration between 30% and 99%; ii) Let halothane, especially trifluoromethane, react with fuming sulfuric acid in an autoclave or laboratory reactor; iii) Set the pressure to 1 to 200 bar; iv) Optionally add peroxides or peroxide salts as defined above as catalysts, if the halocarbon compound includes 1 carbon atom; if the number of carbon atoms in the halocarbon compound> 1, then the stoichiometric amount The amount is added. v) Control the temperature of the reaction mixture at 0 °C to 150 °C, preferably 55 to 100 °C, more preferably 60 to 70 °C; vi) If necessary, purify the reaction product by distillation or extraction.

Example

Example 1 : Fluoroform decomposition to produce fluorosulfuric acid

A 4-liter stainless steel high-pressure reactor containing 1.789 kg of 36% fuming sulfuric acid was charged with 285 grams of fluoroform (4.07 moles). The reactor was sealed and heated to 100 ^o C, and the stirring speed was set to 350 rpm. After 24 hours of constant stirring, the excess pressure was released to a set of scrubbers equipped with sulfuric acid, and the excess fluoroform, if any, was stored in a stainless steel cylinder to prevent the fluoroform from being released into the atmosphere. The pressure in the reactor remains fixed at 30.7 bar, which means the presence of dissolved CF ₃ H in liquid and gaseous CF ₃ H in the upper headspace. The liquid sample was transferred to a J-Young nuclear magnetic tube, and ¹⁹ F NMR relative to the internal standard measurement showed that the yield of fluorosulfuric acid was 20% (based on the initial molar number of fluoroform).

Example 2: Fluoroform decomposition produces fluorosulfuric acid

a) In a 400 ml stainless steel high-pressure reactor containing 288.2 g of 34% fuming sulfuric acid, 19 g of fluoroform (0.27 mol) is added, and the reactor pressure is increased to 17.3 bar. The reactor was sealed and heated to 80 ^o C, and the stirring speed was set to 400 rpm. The initiator was prepared by dissolving 2.65 g of K ₂ S ₂ O ₈ (9.8 millimoles) in 12 ml of H ₂ SO ₄ (98%), and this mixture was added to the reactor via an HPLC pump. After 4 days of stationary stirring, the excess pressure was released to a set of scrubbers equipped with sulfuric acid, and the excess fluoroform was stored in a stainless steel cylinder to avoid direct release to the atmosphere. The liquid sample was transferred to the J-Young nuclear magnetic tube, and ¹⁹ F NMR relative to the internal standard measurement showed that the yield of fluorosulfuric acid was 57% (based on the initial molar number of fluoroform).

b) Prepared without adding additional oxidizing agent: CHF ₃ + 3SO ₃ + H ₂ SO ₄ à 3FSO ₃ H + CO ₂ +SO ₂

A small stainless steel reactor (450 ml, purchased from Parr Instruments) equipped with a glass liner was charged with oleum 65 (292.5 g, 2.37 mol SO ₃ ) at 40°C. Under vigorous stirring, the sealed container was heated to 100°C and reached a pressure of 4.2 bar. Afterwards, the reactor was pressurized with CHF ₃ to a total pressure of 15.3 bar (94 millimoles CHF ₃ ). The reaction mixture was stirred (900 rpm) for an additional 22 hours. Then, the reactor was cooled to 40°C, and all volatiles were released to the scrubber containing sulfuric acid. The liquid reaction mixture was recovered and stored in a 100 ml glass SCHOTT bottle.

A small amount of sample (approximately 0.7 ml) is delivered to a nuclear magnet tube with a Teflon cover, and analyzed by a ¹⁹ F{ ¹ H} NMR spectrometer. The FSO ₃ H production (28.2 g, 282 millimoles) was measured by comparing the relevant peak integral value with the internal standard (C ₆ F ₆ ), showing that CHF _{3 was} quantitatively converted into FSO ₃ H.

Example 3: Decomposition difluoromethane (CH ₂ F ₂₎ of

A small stainless steel reactor (450 ml, purchased from Parr Instruments) equipped with a glass liner was pressurized with CH ₂ F ₂ at 60°C to a total pressure of 15.1 bar (0.243 millimoles CH ₂ F ₂ ); reaction 1 . Then, oleum 35 (307.2 grams, equal to 1.23 moles of SO ₃ ) was pumped to the reactor. The temperature was maintained at 50°C and a pressure of 19.2 bar was observed. With stirring (900 rpm), the pressure is reduced to 11.5 bar. Under vigorous stirring, the sealed container was heated to 60°C. After 30 hours, the pressure dropped to atmospheric pressure. A small amount of samples were taken from the reactor for ¹⁹ F NMR spectrum analysis. After that, the reactor was pressurized with 12.8 bar CH ₂ F ₂ (0.20 mol) at 60°C for the second experiment. After 36 hours, the reactor pressure reached 1.5 bar; reaction 2 .

The yield of FSO ₃ H in reaction 1 (45.1 g, 0.451 mol, 93% relative to CHF ₃ yield) was measured by comparing the integrated value of the relevant peak with the internal standard (28.8 mg C ₆ F ₆ ). ¹⁹ F{ ¹ H} (40.89 MHz) NMR s 45.7 (FSO ₃ H); s 161.5 ppm (C ₆ F ₆ ) ppm.

The reactor was cooled to 40°C, and all volatiles were released to the scrubber containing sulfuric acid. The liquid reaction mixture was recovered and stored in a 100 ml glass SCHOTT bottle. A small amount of sample (approximately 0.7 ml) was transferred to a nuclear magnetic tube with a Teflon cover, and analyzed by a ¹⁹ F{ ¹ H} NMR spectrometer, which showed that CH ₂ F _{2 was} converted into FSO ₃ H and the organic product ethylene disulfate (MDS, CH ₂ (SO ₄ H) ₂ ).

The yield of FSO ₃ H in reaction 2 (the second CHF ₃ charge) (28.4 g, 0.284 mol, relative to the yield of CHF ₃ is 70%) is based on the relevant peak integral value and internal standard (C ₆ F ₆ ) Measured by comparison.

Example 4 : Effective decomposition of dichloromethane ( CH ₂ Cl ₂ ) without catalyst

A Fisher Porter pressure reaction vessel equipped with a pressure gauge and a magnetic stirring rod was filled with Oleum 34 (27,277 g). Without cooling, dichloromethane (DCM, 3 mL) was slowly added directly to the fuming sulfuric acid. Be careful, because when DCM is not carefully added dropwise, the reaction is violent. The reaction mixture formed two phases. The Fisher Porter vessel was closed and the mixture was heated to 90°C under vigorous stirring. After 3 hours, the stirring was stopped and the reaction mixture was allowed to cool to room temperature. At this time, there is no phase separation.

After that, a small amount of sample (approximately 0.7 ml) was transferred to a nuclear magnetic tube with a Teflon cap, and analyzed by ¹ H and ¹³ C{ ¹ H} and ¹³ C ¹ H HSQC NMR spectrometers, which showed that CH ₂ Cl _{2 was} completely converted ( s, 5.36 ppm, ¹ H NMR) and the formation of the main product, methylene bis(chlorosulfate) MBCS ( ¹ H NMR br s, 6.07 ppm, ¹³ C{ ¹ H}, NMR s 91.77 ppm).

When there is excess CH ₂ Cl ₂ , chloromethyl chlorosulfate (CMCS) is subsequently formed.

The following NMR chemical shifts (ppm) are reported by Bethell et al. in Org. Biomol. Chem. 2004, 2, 1554-62. MBCS : ¹³ C: 92.18 ¹ H: 6.14 in CDCl ₃ ; CMCS : ¹³ C: 77.32 ¹ H: 5.96 in CDCl ₃ . Found NMR chemical shifts (ppm): MBCS : ¹³ C: 91.77 ¹ H: 6.07 in H ₂ SO ₄ ; CMCS : ¹³ C: 76.00 ¹ H: 5.86 in H ₂ SO ₄ .

Isolation: MBCS and CMCS can be extracted from the reaction mixture: the reaction mixture is carefully treated with water to quench the residual SO ₃ . The mixture was then extracted three times with dichloromethane (about 3 ml per extraction). The organic layer was filtered through a PTFE syringe filter, and all volatiles were evaporated under atmospheric pressure to obtain a pure product.

Example 5 : Preparation of fluorosulfonic acid ( FSO ₃ H ) by thermal decomposition of 1,1,1,2- tetrafluoroethane ( R134 ) in fuming sulfuric acid R134 + fuming sulfuric acid 34 + excess K ₂ S ₂ O ₈ à 3FSO ₃ H + CO ₂ (90°C, 5 bar)

The high-pressure nuclear magnetic tube (NORELL, EXTREME series grade 3, thin wall, Kalrez O-ring) is filled with 0.5 ml of oleum 34 (Oleum 34), and then 5 bar 1,1,1,2-tetrafluoroethane (R134 ) Pressure. After the reaction, ¹ H and ¹⁹ F NMR spectrum analysis was performed. Starting material: ¹⁹ F (40.89 MHz) of R134 in oleum 34 NMR: -75,5 (3F, dt, J=15.9; 8.1 Hz, C F ₃ ); -236.4 (1F, tq J=45.5 ; 15.6, ppm, CH ₂ F ) ppm. ¹ H NMR (44 MHz) of R134 in oleum 34: 4.77 (2H, dq, J=45.1; 8.1 Hz, C H ₂ F).

At 85°C without using an oxidizing agent, no formation of FSO ₃ H was detected after 16 hours. Adding excess K ₂ S ₂ O ₈ can detect the formation of FSO ₃ H, which can be shown by the ¹⁹ F NMR spectrum obtained within 2 hours. After 21 hours at 85°C, 1,1,1,2-tetrafluoroethane (R134) reacted quantitatively, and the FSO ₃ H yield was observed to be 85%. ^{The 1} H NMR spectrum shows that no major non-fluorinated by-products (for example, methylene bis(sulfate) or the like) are formed.

Example 6 : Preparation of fluorosulfonic acid ( FSO ₃ H ) by thermal decomposition of 2,3,3,3- tetrafluoropropene ( R1234yf ) in fuming sulfuric acid R1234yf + oleum 34 + excess K ₂ S ₂ O ₈ à 3FSO ₃ H + CO ₂ (90°C, 5 bar)

The high-pressure nuclear magnet tube (NORELL, EXTREME series grade 3, thin wall, Kalrez O-ring) is filled with 0.5 ml of oleum 34, and then pressurized with 5 bar 2,3,3,3-tetrafluoropropene (R1234yf). After the reaction, ¹ H and ¹⁹ F NMR spectrum analysis were performed. ¹⁹ F{ ¹ H} (40.89 MHz) NMR of R1234yf in oleum 34: a broad single peak (br s) of approximately -74 (br) ppm superimposed on the inherent residual peak of the spectrometer.

When no oxidizing agent is used at ambient temperature, the formation of FSO ₃ H has been detected after 15 minutes. After 1 hour at 90°C, the ¹⁹ F NMR spectrum includes only three single peaks (-70.0; -75.2; -76.4 ppm) in addition to the single peak associated with FSO ₃ H at 44 ppm. Obviously, there is no J coupling, which means that there is only the CF part, but there are no coupled H or F adjacent atoms.

Releasing the pressure did not cause the loss of the unimodal resonance associated with the initially formed by-products, so the intermediate product is not expected to be gaseous. To the mixture was added excess K ₂ S ₂ O ₈ (200 mg). When K ₂ S ₂ O ₈ was added, gas formation was observed violently. The reaction mixture was heated at 90°C for another 6 hours in the closed NMR tube. An increase in the peak area associated with FSO ₃ H is observed. However, the residual peak still exists in the area between -65 and -80 ppm.

R1234yf conversion rate: 100%. Relative to all the F-containing products formed, the yield of FSO ₃ H: 60%.

Example 7 : Preparation of fluorosulfonic acid ( FSO ₃ H ) by thermal decomposition of PFOA in fuming sulfuric acid PFOA + fuming sulfuric acid 34 + excess K ₂ S ₂ O ₈ à 3FSO ₃ H + CO ₂ (80°C)

J Young NMR tube (NORELL) is filled with 0.5 ml of oleum 34 and 15 mg of perfluorooctanoic acid (PFOA). After the reaction, ¹⁹ F NMR spectrum analysis was performed. In the absence of an oxidant, no reaction occurred after 3 hours at 80°C. Add excess K ₂ S ₂ O ₈ and heat the sample at 80°C for 30 minutes. According to ¹⁹ F NMR spectrum analysis, the formation of FSO ₃ H is observed. The reactants were allowed to react overnight (16 hours), PFOA was significantly degraded and the formation of FSO ₃ H was confirmed.

PFOA conversion rate: 70%.

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Claims (16)

A method of converting halocarbon compounds, in which halocarbon compounds react with sulfur trioxide (SO ₃ ). The method according to claim 1, wherein SO ₃ is present as oleum. The method according to claim 1 or 2, wherein the halide compound reacts with SO ₃ to form a corresponding halide sulfonic acid. The method according to claim 1 or 2, wherein the halocarbon compound is a compound in which at least one hydrogen atom in a hydrocarbon is replaced by a halogen, and the hydrocarbon system is selected from alkanes, alkenes, and alkynes, wherein the hydrocarbon may be Linear, branched or cyclic, substituted or unsubstituted. The method according to claim 1 or 2, wherein the molecular ratio of sulfur trioxide to halocarbon compound is in the range of 1 to 100. The method according to claim 1 or 2, wherein the halocarbon compound is reacted with SO ₃ at a temperature of 0 to 200 °C. The method according to claim 1 or 2, wherein the halocarbon compound is reacted with SO ₃ under a pressure of 1 to 200 bar. The method according to claim 1 or 2, wherein the halocarbon compound is a fluoro, bromo or chloro derivative of alkane. The method according to claim 1 or 2, wherein the halocarbon compound includes one or more halogen atoms, wherein one or more carbon atoms of the halocarbon compound are bonded to one or more halogen atoms. The method according to claim 1 or 2, wherein the halogenated carbon compound is a halogenated derivative of a branched or unbranched alkane having a carbon number in the range of 1 to 20. The method according to claim 1 or 2, wherein the peroxide is added to the reaction mixture including the halocarbon compound and fuming sulfuric acid. The method according to claim 11, wherein when the halocarbon compound includes more than 1 carbon atom, the peroxide is added in a stoichiometric amount, and when the halocarbon compound includes 1 carbon atom, the peroxide Add in stoichiometrically (sub-stoichiometrically). The method according to claim 1 or 2, wherein a sulfated intermediate product is produced during the reaction. The method according to claim 13, wherein the sulfated intermediate product can be separated from the reaction mixture. A use of sulfur trioxide in the recovery or disposal of halocarbon compounds. The use according to claim 15, wherein the sulfur trioxide is used for the recovery or disposal of halothane.